Textile fabric



Mmh 6, 1945 D. FINLAYsoN :a1-AL4 TEXTILE FABRIC Filed Nov. 25, 1943 FIG.l

n V I I v F/Gz INV ENTOKS 7m W AvromlEY-S Patented Mar. v6, 1945 UNITEDI STATES ,PATENTOFFICE TEXTILE FABRIC Donald Finlayson and HarryCrawshamspondon,

near Derby, England, assignors to British Celanese Limited, London,England, a company I of Great Britain Appuetimi November 25', 1943,serial No. 511,718

e AIn Great Britain November 19, 1942 (ci. zii-so) i example a i--shaftvsatin, the warps being ar- 17 Claims.

This invention relates to textile fabrics yand is especiallyconcerned'with woven fabrics that are rendered suitable for electricalinsulating purposes' by` treatment with avdrying 4oil or otherinsulating varnish.

Fabrics of this character are generally required to combine extremethinness with a high degree of strength, for which purposes fine yarnsof high .suitableffor oiling or varnishing for use, for example, as anelectrical insulating fabric comprises in both warp and weft, yarns ofgreat ten-l sile strength-and low extensibility and yarns of relativelylow strength and high extensibility woven together in such a way thatthe yarns of low extensibility are not interlaced in any substantialdegree, and preferably not at all, with other yarns of the same kind butdepend entirely or almost entirely for their maintenance in the fabricstructure on the presence of the yarns of high extensibility. When afabric of this kind is treated withan insulating varnish it is found topossess -a muchhigher resistance to tearing then a fabric of similarweight woven from the stronger yarns alone, apparently because there isno tendency for the stronger yarns, not being interlaced with oneanother, to cut intoone another and so localise .the strains on theyarns when the fabric is subjected to a tearing action.

In order to produce the desired effect on the fabric, that the lowextensibility yarns-should not interlace with one another, many dierentarrangements f the ,two lkinds of yarn inthe warp and weft are possible,with corresponding systems or patterns of weaving. The simplestarrangement is a plain weave in which both warp and weft consist of thestronger yarnsalternating one and .onewith the more extensible yarns.Itis often more convenient. however, in the operation of weaving,to'insert picks of the same kind of yarn-in` pairs so that'the yarns ofthe weft alternate two and two. .In this case some other form ranged toalternate one and one.

In such an arrangement, all thelthrewads of one ofthe two warpsheets areof one kind for two successive picks and of the other kind for the nexttwo picks and so on, the threads of the other sheet being always mixed.The effect required for the pur- 1 pose of the present invention canthus be obtained by causing the weft picks to alternate two and two, asstated above, the weft inserted at each pick being different in kindfrom the thread of which the one warp sheet\whollyv consists. In

both of the fabrics mentioned above, not only are the yarns of lowextenslbilitynot interlaced with one another, but thel same is alsotru'e of the yarns of high extensibility, the coherence of the fabricdepending upon the interlacing of the warps of onefkind of yarn with thewefts of the other. Many other arrangements are also possible in whicheach of the two kinds of yarn does not interlace with its.own kind butdepends on yarns of the other kind to hold it in the fabric.v Y

Itis particularly convenient to employ as .the stronger yarn in thefabric continuous lament yarns. of regenerated cellulose of hightenacity,

for example a tenacity in excess of about 2 grams per denier,accompanied Iby a low extensibility, e. g. of the order of 8% or less,the extens1bility Y generally' varying inversely with the tenacity,achieved-,f Such high tenacity yarns 'may be made. for example, by thecomplete saponication of yarns of cellulose acetate or lother organicester of cellulose that has been stretchedto a considerable extent whilein asoftened condition, for example in the presence ofy wet or saturatedsteam or hot water as described in U. S.'Patents Nos. v

2,142,717 and 2,142,722. Again, high tenacity yarns of an organic esterof cellulose, which may saponiiledhigh tenacity celluloseester'materialssubsequently be saponifled', can also be made bywet-spinning processes carried out` under such conditions that thematerials are drawn down considerably as they are extruded, for exampleby several hundred percent ofthe length they would have if extrudedfreely and vwithout; stretch. Again, regenerated cellulose `yarns ofhigh tenacity can alsobe made directly by spinning solutions of viscoseor cuprammonium cellulose under suitable conditions, for 'example undersuch condi' tions that a considerable stretch is effected. AAmongothermaterials of which the' stronger yarns in the fabric may becomposed are un.-

efthe kind referred te above and cellulose ether 0f waive than a plainweave must be adopted, for N5v materials' that in their, manufacturehave bility of'about 15% or somewhat subjected to similar stretchingprocesses for ensuring high tenacity.'

Any suitable fine yarn having a relatively high degree of extensibility,as compared with the high-tenacity yarns, may be employed as the moreextensible yarn; e. g. in-association with high-tenacity lyarns havingan extensibility of 8% or less, low tenacity yarns having anextensibility of 12-20% or more may be used. Thus, for

example, any of the types of yarn mentioned above as being capable ofhaving a high degree of strength imparted to them by stretching them tweil as in the stronger yarn it is preferablethat the yarn shouldconsist of continuous filaments,

' as from such yarns thinner fabrics of a given weight may be producedthan vfrom yarns consisting of or containing staple lengths of fibre.

As typical of the high-tenacity low-extensibility yarns of regeneratedcellulose previously described may be mentioned a continuous filament'in or run through a hot tower for an appropriate period.

The following is givenas an example of a fabric in accordancewith thepresent inven-v tion z Example The warp bf the-fabric comprises yarns of30 denier of continuous filaments made by stretching continuousfilaments of cellulose acetate and subsequently saponifyingsubstantially completely the stretched yarn. These yarns alternate with.yarns of 45 denier made of unstretched and unsaponied cellulose acetatefilaments, the two kinds of yarn alternating end and' end in the warp.Similar yarns are employed in the weft but in this case the picks ofweft alternate two and two instead of one and one. The warp and weft arewoven together to form a 4-shaft satin fabric with 100 ends per inch inthe warp and 140 picks per inch in the weft.I The fabric so produced istreated with an insulating varnish hav,-` lng as its basis a glycerol/phthalic-anhydride resin which has been modified with linseed oil, andcontaining about 60% 0f the modified resin together with ahydrocarbonthinner.

The fabric is run through a bath of the varnish and drawn verticallyupwards, as it leaves the yarn made from cellulose acetate filaments by.

stretching .such filaments in the presence of wet steam to about'l tentimes their original length,

and then completely saponifying them. The regenerated cellulose yarnthus produced may have' atenacity exceeding 4 grams per denier and anextensibility of 5-6%'.v Such high-tenacity yarns may be used inconjunction with continuous lilament yarns of cellulose acetate spun inthe ordinary way, which will generally have an extensimore.

' it encounters the blade.

As the insulatingvarmsh with which the fabric l according to the presentinvention is to be treated to render it more suitable as' an insulatingmaterial, any appropriate composition may be employed that has noinjurious effect on the stronger yarn contained in the fabric, andpreferably none on either of the kinds of yarn. Insulating var' nishesof the type commonly employed and comprising a basis of a drying oil,such as linseed or China-wood oil, together with other ingredi` ents, e.g., driers, softeners and the like may be used. Other var-nishes,however, maybe used having a basis of a material capable on drying offorming a exible nlm, e. g. oil-modied resins such as oil-m'oded alkydor phenol-formaldehyde resins. While it generally preferable that thevarnish should be without injurious effect on the more extensible aswell as Aon the poses, so to select the varnish and the Anature of themore extensible yarn that the latter is destroyed, orrendered veryA weakby the application of the varnish. By these means any tendency for eventhe mor extensible yarns to lo-h calise the stresses on the strongeryarns is avoided.

In this case the stronger yarns are held together in the finishedproduct by the film that-isA formed by the varnishon' drying.

i stronger yarns, it'is possible, for particular purtherewith. Similarlyall the unshaded weft yarns.

bath, past a doctor blade to remove excess varnish.

' The fabric then passes up a drying tower through which air heated to atemperature of C. is passed. The amount of varnish taken up by thefabric may be adjusted by adjusting the temperature (and therefore theviscosity) of the varnish, and by varying the height of the doctor bladeabove the surface of the bath so as to vary the degree of drying of thefabric before A fabric of the kind described above may, in this way, begiven a finished thickness of from 4 mils. upwards. Thicker fabrics may,ofcourse, be produced by using yarns of greater weight.

vWhile the invention has been described above in connection with fabricsintended to be usedv present invention are shown in the accompanyingdrawing in which Figure 1 is a diagrammatic view of a plainwoven fabricand Figure 2 is a diagrammatic view of a 4- shaft ,fsatin fabric, bothfigures showing the manner in which the yarns of the fabrics areinterlaced.

In Figure 1, which shows a plain-woven fabric,

the yarns of high tensile strength and relatively low extensibilityare-shown at I and the yarns of low strength and high extensibility at2, the yarns of the first kind being distinguished from those of thesecond kind by being lshaded while' those of the second kind are shownplain. It

will be seen that the -yarnsof the two kinds al-y ternate witheach otherin both warp and weft, and as a result all theshaded weft yarns lie overall the shaded .warp yarns and arenot interlaced lieover all theunshaded warp yarns. Nevertheless, the cohesion of the fabric is broughtabout by the fact that the unshaded weft yarns, though passing over theunshaded warp yarns, pass under the shaded warp yarns while the unshadedwarp yarns, though passing'under the unshaded u weft yarns. pass overthe shaded weft yarns.

l. It will be seen that the shaded warp Yyarns j pass over all theshaded weft yarns and that the unshaded warp yarns pass over allthe-unshaded weft yarns. The coherence of the yfabric is brought about,however, by the Yfact that the shaded warp yarns pass under one-half ofthe unshaded weft yarns while the unshaded warp yarns pass underone-half of the shaded weft yarns. Thisarrangement depends on thedisposition ofthe shaded and unshaded pairs of weft kinds alternate twoand two, as previously stated.

Having described our invention, what we desire to secure by LettersPatent is: l

l. A fabric suitable for use as the basis of a varnished fabric,comprising in both warp and weft, yarns of high tensile strength and lowextensibility and yarns of relatively low tensile strength and highextensibility, said yarns being so woven together that the yarns of lowextensibility are not interlaced with one another to any substantialdegree but depend substantially entirely for their maintenance in thefabric structure on the presence of the yarns of high extensibility.

2. A fabric suitable for use as the basis of a a varnished fabric,comprising in both warp and weft, yarns of high tensile strength `and.low extensibility and yarns of relatively low tensile strength and highextensibility, said yarns beingv so woven together that the yarns of lowextensibility are not interlaced with one another to any substantialdegree and the yarns of high extensibility are not interlaced with oneanother to any substantial degree, the yarns of each of the two kindsdepending substantially entirely for their maintenance in the fabricstructure on the presence of the yarns of the other kind.

3. A fabric suitable for use as the basis of a varnished fabric,comprising in both warp and weft, yarns of high tensile strength and lowextensibility and yarns of relatively low tensile strength and highextensibility, said yarns being so woven together that the yarns of lowex In this fabric', the warp' the two kinds depending substantiallyentirely for their maintenance in the fabric structure on the presenceof the yarns of the other kind, the

fabric having a 4-shaft satin weave wherein the yarnsalternate one andone in the warp and two and two inthe weft.

5. A fabric suitable for use as the basis of a varnished fabric,comprising in-both warp and weft, regenerated cellulose yarns of lowextenssibility that have been subjected to a high degre'e of stretch inthe course of their production weft, continuous lament yarns of lowextensilto as to impart a high tenacityto them, and

yarns of relatively low tensile strength and high extensibility, saidyarns'being so woven together that the yarns of low extensibility arenot interlacedr with one -another to any substantial degree but dependsubstantially' entirely for their maintenance in the fabric structure onthe presence of the yarns of high extensibility.

6. A fabric suitable for use as the basis of a varnishedfabric,.comprising in both warp and weft, regenerated cellulose yarns oflow extensibility that have been subjected to a high degreeof stretch inthe course vof their production so as to impart a high tenacity to them,and yarns of relatively low tensile strength and high extensibility,said yarns being so woven together that the yarns of low extensibilityare not interlaced with one another to any substantial degree, and theyarns of high extensibility are not interlaced with one another to anysubstantial degree, the yarns of each of the two kinds dependingsubstantially entirely for the maintenance in the fabric structure onthe presence of the yarns of the other kind, the'fabric having .a4-shaft satin weave wherein the yarns alternate one and one in the warpand two and two l in the weft.

being sov woven .together that the yarns of low extensibility are notinterlaced with one another to any substantial degree but dependsubstantially entirely for their 'maintenance in the fabric structure onthe presence of the yarns of high extensibility. v

l8. vA fabric suitable for use as the basis of a varnished fabric,comprising in both warpand bility made by .saponifying cellulose esterfilaments that have been stretched so as to impart a y high tenacity tothem, and yarns of relatively l another to any substantial degree andthe yarns weft, yarns of high tensile strength and low ex- Y tensibilityand yarns of relatively low4 tensile strength and high extensibility,said yarns being so woven togethervthat the yarns of low extensibilityare not interlaced with one another to any substantial degree and theyarns of high extensibility are not interlaced with one another to anysubstantial degree, the yarns of each of of high extensibility are notinterlaced with one another to any substantial degree, the yarns of.each of the two lkinds vdepending substantially entirely for theirmaintenance in the fabric structure r`on the presence of the yarns vofthe other kind; the fabric'having a 4shaft satin weave wherein the yarnsalternate one and one inthe warpand .two and two in the weft.

-9. A fabric suitable for use at the basis of varbility, andthermoplastic yarns of relatively low tensile strength and highextensibility, said yarns beingso wovenv together that the yarns of low7. A fabric suitable for us as the' basis of a yextensibility are notinterlaced with one another to anysubstantial degree but dependsubstantiallyy entirely for their maintenance in the fabric structure onthe presence of the yarns of high extensibility.

10. An insulating fabric comprising a basis of tial degree but dependsubstantially entirely for their maintenance in the fabric structure onthe presence of the yarns of high extensibility, said woven fabric beingimpregnated with an insulating varnish that is inert to the materials ofwhich the low extensibility yarns consist.

11. An insulating fabric comprising a basis of woven fabric, comprisingin both warp and weft, yarns of high tensile strength and lowextensibility and yarns of relatively low tensile strength and highextensibility, said yarns being so woven together that the yarns of lowextensibility are not interlaced with one another to any substantialdegree and the yarns of high extensibility are not interlaced with oneanother to anyv substantial degree, the yarns of each of the two kindsdepending substantially entirely for their maintenance in the fabricstructure on the presence of the yarns of the other kind, the fabrichaving a 4-shaft satin weave wherein the yarns alternate one and one inthe warp and two and two in the weft, said fabric being impregnatedwith'an insulating varnish that is inert to the materials of which thelow extensibility yarns consist.

-12. An insulating fabric comprising a basis of woven fabric,.comprisingin both warp and weft, regenerated cellulose yarns of lowextensibility that have been subjected'to a high degree of stretch inthe course of their'production so as to impart a high tenacity to them,and yarns of relatively low tensile strength and high'extensibility,said yarns being so woven together that the yarns of low extensibilityare not interlaced with one another to any substantial degree and theyarns of high extensibility are not interlaced with oneanother to anysubstantial degree, the yarns of each ofthe twov kinds dependingsubstantially entirely for their maintenance in the fabric structure onthe presence of the yarns of Athe other kind, the fabric havingali-shaft satin weave wherein the yarns alternate one and one 55 theyarns of low extensibility are not interlacedin the warp. and "two-andtwo in the weft, said fabric being impregnated with an insulating var'-nish that is inert to the materials of which the low extensibility yarnsconsist.

13. A fabric suitable for use as the basis of a. varnished fabric,comprising in both warp and weft, continuous filament yarns of low.extensif bility made by saponifying cellulose ester filaments that havebeen subjectedto a high degree 'of stretch in the course of theirproduction so as with one another to any substantial degree;the

yarns of each of the two kinds depending substantially entirely fortheir 4maintenance in the fabric structure on the presence 4of the yarnsof the other kind, the fabric having a 4-shaft satin weave wherein theyarns alternate onaand one in the warp and two and two in the weft, saidj 4 gamme fabric being impregnated with an insulating varnlsh that isinert to the materialsv of which the low extensibility yarns consist.

14. An insulating fabric comprising a basis of 5 woven fabric,comprising in both warp and weft,

regenerated cellulose yarns'of low extensibility that have beensubjectedto a high degree of stretch in the course of their production so as toimpart a high tenacityto them, andyarns of relatively low tensilestrength andhigh extensibility, said yarns being so woven together that'the yarns of low extensibility are not interlaced with one another toany substantial degree and the yarns of high extensibility are notinterlaced with one'another to any substantial degree-the yarns of eachof the two kinds depending substantially entirely for their maintenancein the fabric structure on the presence of the yarns of the other kind,the fabric having a 4-shaft satin 420 weave wherein the yarns alternateone and one adrying oil.-` 15. A fabric suitable foruse as the basis ofa varnished fabric, comprising in both warp and weft, continuousfilament yarns of low extensibility made by saponifying cellulose esterfilaments that have been subjected to a high degree of stretch in thecourse of their production so as to impart a high tenacity to them, andyarns of relatively low tensile strength and high extensibility, saidyarns being so woven together that the yarns of low extensibility arenot interlaced with kind, the fabric having a i-shaft satin weavewherein the yarns alternate one and one in'the warp and two and two inthe weft, said fabric being impregnated with an insulating varnish thatis inert to the materials of which the low extensibility yarnsconsist,and has a basis of a drying oil. i

16. An insulating fabric comprisinga basis of woven fabric, comprisingin both warp and weft,

vregenerated cellulose yarns of low extensibility that have beensubjected 'to a high degree of stretch in the course of their productionso as to impart' a high tenacity to them, and yarns of relatively lowtensile strength and high extensibility, said yarns being so woventogether that Withone another to any substantial degree and the yarns ofhigh extensibility are not interlaced with one another to anysubstantial degree, the yarns of each of the two kinds dependingsubstantially entirely for their maintenance in the Kfabric structure onthe presence of the yarns of the other kind, the fabric having a 4-shaftsatin weave wherein the yarns alternate one and one in the warp and twoand twoV in the weft, said fabric being impregnated with an insualtingvarnish that is inertto the materials of which thelow extensibilityyarns consist, and has a basis of an oil-modied alkyd resin.

17` A'fabric suitable for use as the basis of a varnished fabric,comprising in both warp or weft, continuous lament yarns of low extensi^bility, made by saponifying cellulose ester fila,- -ments that have beenlsubjected to a high degree of stretch in the course of 'theirproduction so as 'Il to impart a high tenacity to them, and yarns ofrelatively low tensile strength and high extensibility, said yarns beingso woven togetherthat the yarns of low extensibility are not interlacedwith one another to any substantial degree, the yarns of each of the twokinds depending substantially entirely for their maintenance in thefabric structure on the presence of they yarns of theother kind, thefabric having a 4-shaft satin weave wherein the yarns alternate one andone in the warp and two and two in the weft, said fabric beingimpregnated with an insulating var-- nish that is inert to the materialsof which thu low extensibility yarns consist, and has a basic of anoil-modified alkyd resin.

DONALD FINLAYSON. HARRY CRAWSHAW.

